CVE-2026-20256
MEDIUM WAF: Medium
CVSS 5.7
Published: 2026-06-10
CWE-20
In Splunk Enterprise versions below 10.2.4, 10.0.7, 9.4.12, and 9.3.13, and Splunk Cloud Platform versions below 10.3.2512.13, 10.2.2510.15, 10.1.2507.23, and 9.3.2411.132, a low-privileged user that does not hold the 'admin' or 'power' Splunk roles could cause data exfiltration through classic dashboards by redirecting a victim to an external site using a protocol-relative URL in a drill-down link.
The vulnerability exists because the URL classifier in classic dashboards only recognizes `http://` and `https://` schemes when checking for external URLs. Protocol-relative URLs such as `//attacker.com` bypass this check entirely, and Splunk Web does not show the external-navigation warning dialog to the victim.
WAF Coverage Analysis
Improper Input Validation
Medium WAF Coverage
OWASP: A03:2021 Injection
920xxx - Protocol Enforcement 941xxx - XSS / XXE 942xxx - SQL Injection
Affected Software
| Vendor | Product | Version |
|---|---|---|
| splunk | splunk | 9.3.0 - 9.3.13 |
| splunk | splunk | 9.4.0 - 9.4.12 |
| splunk | splunk | 10.0.0 - 10.0.7 |
| splunk | splunk | 10.2.0 - 10.2.4 |
| splunk | splunk_cloud_platform | 9.3.2411 - 9.3.2411.132 |
| splunk | splunk_cloud_platform | 10.1.2507 - 10.1.2507.23 |
| splunk | splunk_cloud_platform | 10.2.2510 - 10.2.2510.15 |
| splunk | splunk_cloud_platform | 10.3.2512 - 10.3.2512.13 |
References
- advisory.splunk.com (Vendor Advisory)